Xerography is a printing process in which very fine powder referred to as “toner” is applied to paper or other material to form an image. Photocopiers, printers, plotters, and facsimile machines are examples of devices that may utilize a xerographic printing or imaging process. As used in this disclosure “xerographic device” encompasses any type of device using a xerographic imaging process. All xerographic devices require a supply of toner for use in the xerographic process. Because the toner supply in a xerographic device is used up in the printing process, the toner supply must be replenished periodically.
Toner is commonly supplied in a cartridge that includes a toner bin or hopper. The cartridge also commonly includes other components of the xerographic device. For example, toner cartridges commonly include an organic photo conductive (OPC) roller assembly used in the xerographic process. This OPC roller assembly includes a roller referred to as a “drum” and a bearing structure for receiving an axle associated with the drum and supporting the drum for rotation in the cartridge. In the xerographic printing process the drum is exposed to the paper on which the image is to be transferred. Thus, in many types of cartridges the drum is mounted adjacent to a slot or opening in the cartridge with a portion of the drum extending out through the slot in an exposed position.
Because the surface of the drum is susceptible to scratches and other damage that diminishes imaging quality, the drum must be covered or otherwise protected during times when the cartridge is not installed in a xerographic device. Some prior xerographic device cartridges have included a shutter mechanism for protecting the xerographic drum in the cartridge while the cartridge is not installed in a printer. The shutter mechanism is configured to automatically retract to expose the drum as the cartridge is installed into a xerographic device. These shutter mechanisms had the advantage that they did not require the consumer to modify the printer cartridge or remove anything prior to installing the cartridge. Shutter mechanisms were, however, expensive to manufacture and were themselves subject to damage that could prevent them from operating properly. Thus, many current xerographic device cartridges eliminate the shutter mechanism and instead use a removable cover to protect the drum. This removable cover must be physically removed by the user before installing the cartridge into the xerographic device.
Some xerographic device cartridges that eliminate the shutter mechanism are shipped from the original equipment manufacturer with a hard plastic cover that connects over the bearing structure associated with the drum included in the cartridge. As with any fixed cover, this plastic cover must be removed by the user prior to inserting the cartridge into the xerographic device.
Cartridges which are originally supplied with xerographic devices are commonly intended to be disposable after a single use. However, because the cartridges include a large number of relatively complex and expensive components, using these cartridges only a single time is expensive and wasteful. For this reason a cartridge recycling industry has developed to refurbish and recycle used cartridges. Refurbishing a used cartridge involves at least refilling the depleted toner bin with toner, and may include other tasks. Where the cartridge includes an exposed drum, the cartridge recycler must again protect the exposed drum prior to shipping the refurbished cartridge.
The requirement of protecting the exposed drum in many newer xerographic cartridges has posed problems for the cartridge recycling industry. The hard plastic covers that attach over the bearing structures for the drum are specific to the particular cartridge. That is, a cover suitable for one cartridge cannot be used with another type of cartridge. This is a problem for a toner cartridge recycler because it requires the recycler to maintain a separate stock of covers (assuming the covers are even available) for each type of printer cartridge the recycler handles. In order to reduce costs, some recyclers have been using flat paper or cardboard covers that are simply taped on over the exposed drum. However, the flat paper or cardboard covers touch the drum surface and this contact may damage the drum. Thus, there is a need particularly in the xerographic device cartridge recycling industry for a better way to cover and protect the exposed drum in a cartridge while the cartridge is in storage or in transit.